I've got'em somewhere. If you go through JH's PS3100 clone, you'll find a modified version of it that he did, which no doubt sounds absolutely out of this world. But, I'll check my archives - I still have it on breadboard, as a matter of fact (very, very sweet function).

Thanks Yves!
I trawled through Jürgens pages on the PS3100, but all I could find (that I could partially understand) was this:. But where is the filter core?
I would like to see what he's done with it, but then again, the circuit looks so simple, even I could probably breadboard it!
I assume those vactrols are VTL5C3/2 types? Or is there some sort of mojo in having 2 separate LED's shine on 2 separate photocells (relating to, say, a diode drop between the 2 LED's in series)?

Hmm, yes I suppose Babelfish helps a bit.
One thing is a bit unclear to me though: is it the filter resonance that is under cv-control, or the frequency? I don't see a frequncy control anywhere, so it would appear that those are preset values...

No, it's the frequencies of the three cells that are under CV, the resonance of these filters is fixed (and is around Q=5).

If you look at the schematic ps-3100-res-2.gif from RJB, you have three pots called 1st peak, 2nd peak and 3rd peak. These let you set the central frequency of each filter. Then a CV applied either to point 7 or 8 or ps-3100-res-2.gif let you modulate the frequencies of all filters.
If you wish you can add also a separate CV for each filter by adding a separate input resistors at the bases of Q102,Q103 and Q104._________________Yves

If you wish you can add also a separate CV for each filter by adding a separate input resistors at the bases of Q102,Q103 and Q104.

I highly recommend this, too - it really adds a lot to the function of the resonator. JH took real advantage of this, and, if I'm not mistaken, was instrumental in the development of the MAM RS3, which is based on the resonator circuit. To get an idea of the effect that can have, read this:

First time I ever heard one was on Jeff Pontius' SynthImagery album. I emailed him and asked him what kind of crazy phase shifter he had - he replied that it wasn't a phase shifter, but was in fact the RS3. Later, the first time I visited him, he let me play his Prophet 5 through it - I literally went weak in the knees, it sounded *that* good.

Ah, thanks for pointing that out to me!
I saw the vactrols, but not the opamps I thought were supposed to be there.
I guess JH used discretes instead.

Vactrols:
If I understand those numbers correctly, then the 5C4/2 is a lot slower to turn on and off, than the 5C3/2, yes?
Which would give a more sluggish, "muddy" sound, I guess.
Don't know if that's desirable in this case, but then JH used them, so...

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